Cashing in on the bitcoin boom: Consumers are using bitcoins at coffee shops, hotels, online stores and even,

Duhaney, 37, was in the market for bitcoins, the hot digital currency that has caught the eye of entrepreneurs and regulators. So he ventured to a pair of couches on the supermarket's second floor, next to the Jamba Juice, where enthusiasts meet weekly to buy, sell and talk bitcoins. He quickly found a seller: a quiet young man in a trench coat lounging in a green armchair. Along with a friend who trades so-called crypto currencies, the two used their iPhones to check bitcoin 's going price — then about $830 on a leading online exchange. Then they sealed the deal. Duhaney pulled out $1,005 — 10 crisp $100 bills, and five ones — in exchange for 1.2 bitcoin, which was transferred via an iPhone app. "It looks like something nice to invest in," said Duhaney, a computer programmer who lives in suburban White Plains, N.Y. "Right now, it's taking off." It's a bet speculators like...